TEXT	sqrt(SB), $0
	FMOVD	a+0(FP), F0

	FTST
	WAIT
	FSTSW	AX
	SAHF
	JLO	bad

	FSQRT
	RET

bad:
	FMOVDP	F0, F0
	CALL	NaN(SB)
	RET
